Endoscopic aspiration device

ABSTRACT

An endoscopic aspiration device is mounted on a manipulating head of an endoscope, from which an elongated insertion rod member is extended forward, the endoscopic aspiration device being composed of a valve casing which is mounted on the manipulation head in communication with an aspiration passage running through the insertion rod member, and a valve assembly unit including a valve member, a valve guide member and a connector member attached to the valve guide member to communicate same with a proximal aspiration passage on the side of a suction source. The valve member is put in a sliding displacement along the valve guide member to bring the aspiration passage into and out of communication with the proximal aspiration passage on the side of a suction source. The valve guide member is coupled with the valve casing through a coupling mechanism which permits to turn the valve assembly unit on and relative to the manipulating head. The coupling mechanism is arranged to perform a function of coupling and uncoupling the valve guide unit with and from the valve casing, and a function of locking the valve guide member in the valve casing to prevent spontaneous dislodgement from the latter.

This application is a Divisional of co-pending application Ser. No.12/392,806, filed on Feb. 25, 2009, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120.

TECHNICAL FIELD

This invention relates to an endoscopic aspiration device to be used onan endoscope for aspirating internal filth and body fluids from a bodycavity.

TECHNICAL BACKGROUND

Generally, an endoscope is composed of a manipulating head and anelongated insertion instrument which is extended forward from themanipulating head for introduction into a body cavity in need of anendoscopic examination or treatment. In endoscopic examinations andtreatments, an aspiration mechanism on an endoscope is resorted to forthe purpose of observing an intracavitary site of interest in a clearlyvisible state. Namely, in case an intracavitary site under observationor treatment is covered with internal filth or body fluids like blood tosuch a degree as to make it difficult to observe the intracavitary sitein question clearly, an aspiration mechanism is turned on to suck outcovering internal filth and body fluids. In this regard, it has been theusual practice to utilize as an aspiration passage a tool introductionchannel which is provided on an endoscope for introduction of forceps orother surgical instruments into a body cavity. In some cases, anaspiration passage is provided separately from a tool introductionchannel. Anyway, an endoscopic aspiration device including an aspirationvalve and a valve operating member is mounted on a manipulating head ofan endoscope. The aspiration valve is connectable to a proximalaspiration passage from a suction source, so that aspiration can becarried out for a necessary time period by manipulation of theaspiration valve operating member.

By the way, not only aspiration passages including a tool introductionchannel of an endoscope and interiors of an aspiration valve but alsointeriors of a proximal aspiration passage on the side of a suctionsource unavoidably get contaminated by the use of an endoscopicaspiration device. Therefore, all of contaminated aspiration passages intransit have to be completely washed and disinfected before using theendoscope again. However, an aspiration valve which is adapted to bringaspiration passages into and out of communication with a proximalaspiration passage on the side of a suction source is complicate inconstruction, so that it has been extremely difficult to completely washthe entire routes of aspiration through and to and from an aspirationvalve which is mounted on a manipulating head of an endoscope.

With a view to solving the problem as mentioned above, for example,Patent Literature 1 below discloses an aspiration valve which isimproved in washability. In Patent Literature 1, an aspiration passagewhich is provided internally of an elongated insertion rod member as faras an opening at a fore distal end of the insertion rod member isconnected with a proximal aspiration passage on the side of a suctionsource at a point on a manipulating head of the endoscope. In order toconnect and disconnect the aspiration passage to and from the proximalaspiration passage, a proximal end of the aspiration passage isconnected to a valve casing within a housing of the manipulating head,and an external valve assembly unit is disconnectibly connected to thevalve casing. The external valve assembly unit is constituted by a valveguide member which is adapted to be disconnectibly connected to thevalve casing, and a valve member to be slidably fitted in the valveguide member. A connector pipe is provided at a lateral side of thevalve guide member for disconnectibly connecting thereto a proximalaspiration passage on the side of a suction source.

One end of the valve member, i.e., an end away from a valve body at theother end, is arranged to serve as an aspiration trigger portion whichis designed to be manipulated by a finger of an operator's hand whichgrips the manipulating head of the endoscope. The valve body is locatedin the valve casing, normally blocking communication between theaspiration passage and proximal aspiration passage. As the aspirationtrigger portion is pushed in, the valve body is caused to slide alonginner surfaces of the valve casing to open the communication between theaspiration passage and the proximal aspiration passage. As a result, thevacuum pressure from the proximal aspiration passage comes to prevail inthe aspiration passage to apply a suction force to an opening at thedistal end of the insertion rod member.

The aspiration takes an internal route through the insertion rod memberand as far as the manipulating head of the endoscope, and then takes anexternal route which is led out from a housing of the manipulating head.A flexible tube of a proximal aspiration passage, i.e., a passage on theside of a suction source, is connected to a connector pipe which isextended out from the above-mentioned valve guide, which is projected onthe housing of the manipulating head. When an operator grips themanipulating head in his or her hand to operate the endoscope, however,the connector pipe and the flexible proximal aspiration passage areoften found obstructive of the operation of the endoscope. For thisreason, the valve assembly unit is arranged to be turnable relative tothe valve casing, permitting to turn the connector pipe and the flexibleproximal aspiration passage out of the way of manipulation of theendoscope.

The above-mentioned valve assembly unit is disconnectible from the valvecasing. After each use, the valve assembly unit is dismantled from thevalve casing and a cleaning brush is inserted into the aspirationpassage for washing same completely. The flexible proximal aspirationpassage which is connected to the valve assembly unit and connector pipecan be reused after washing or may be simply discarded and replaced by anew one.

-   Patent Literature 1 Japanese Laid-Open Patent Application    2007-252589

SUMMARY OF THE INVENTION Problem(s) Solved by the Invention

As mentioned hereinbefore, in Patent Literature 1 above, for the purposeof improving washability, a proximal aspiration passage on the side of asuction source is led out from a valve assembly unit in a valve casing,instead of taking a route through a universal connection cable which isconnected to a manipulating head of the endoscope. The aspiration valveemployed in Patent Literature 1 is improved in washability but still hasa problem. Namely, the valve assembly unit which is detachablyconnectable to the valve casing on the manipulating head of an endoscopein such a way that a connector pipe and proximal aspiration passage onthe side of a suction source can be turned to a position out of the wayof manipulations of the endoscope, using a coupling mechanism which isadapted to lock the valve assembly unit in the valve casing byengagement of a stopper protuberance which is provided on the part ofthe valve casing, with a interlocking projection which is provided onthe part of the valve guide member and adapted to ride over the stopperprotuberance on the side of the valve casing.

In order to prevent spillage of internal filth and body fluids likeblood which are being aspirated through an aspiration passage, the valveguide member should be coupled with the valve casing in such a way as topreclude possibilities of dislodgement of the valve guide member fromthe valve casing on the manipulating head of the endoscope. For thispurpose, the valve guide member needs to be connected fast to the valvecasing, for example, by increasing the height of the interlockingprojection and stopper protuberance to such a degree which is sufficientenough for preventing fall-off or slip-off of the valve guide member.However, it is very likely that the use of higher interlockingprojection and stopper protuberance will make it difficult to extractthe valve guide member from the valve casing for washing purposes eachtime after using an endoscope.

In view of the above-discussed problem with the prior art, it is anobject of the present invention to provide an endoscopic aspirationdevice having a pipe of a proximal aspiration passage on the side of asuction source detachably connected to an aspiration valve, a valveassembly unit of the aspiration valve being coupled with and uncoupledfrom a valve casing on a manipulating head of an endoscope in afacilitated manner and securely locked in a coupled position within thevalve casing once fitted into the latter.

It is another object of the present invention to provide an endoscopicaspiration device which is adapted to retain a valve assembly unitsecurely in position within a valve casing free of possibilities ofdislodgement from the valve casing while manipulating an endoscope, thevalve assembly unit however being easily extractable from the valvecasing, for example, when it becomes necessary to wash the valveassembly unit after use.

Means for Solving Problem(s)

According to the present invention, in order to achieve the above-statedobjectives, there is provided an endoscopic aspiration device for use ona manipulating head of an endoscope, to which a proximal end of anelongated insertion rod member is connected, the endoscopic aspirationdevice comprising a valve casing provided on the manipulating head incommunication with an aspiration passage leading to a fore distal end ofthe insertion rod member, and a valve assembly unit composed of anassembly of a valve member and a valve guide member having a connectormember extended out for connection to a proximal aspiration passage onthe side of a suction source, the valve member being put in a slidingdisplacement along the valve guide member to bring the aspirationpassage into and out of communication with the proximal aspirationpassage, characterized in that the endoscopic aspiration devicecomprises: a coupling mechanism provided between the valve casing andthe valve guide member of the valve assembly unit and adapted to couplethe valve guide member with the valve casing in such a way as to permitthe valve assembly unit to make turns about a center axis of the valvecasing on the manipulating head; and the coupling mechanism including acoupling/uncoupling mechanism with a function of bringing the valveguide member of the valve assembly unit into and out of fittingengagement with the valve casing, and a lock-in mechanism with afunction of retaining the valve guide member in a coupled state withinthe valve casing, preventing spontaneous dislodgement of the valveassembly unit from the valve casing.

A valve assembly unit which is largely composed of a valve guide memberand a valve member is detachably fitted in a valve casing which isprovided on the side of a manipulating head of an endoscope. In thisregard, arrangements should be made to prevent spontaneous dislodgementof the valve assembly unit from the valve casing. In order to preventthe valve assembly unit from easily coming off the valve casing, itshould be securely locked in the valve casing while the endoscope is inuse including an aspirating operation. However, at the time of washingthe endoscope after use, the valve assembly unit including the proximalaspiration passage on the side of a suction source should be easilyuncoupled and dismantled from the valve casing.

A valve guide member of a valve assembly unit should be coupled with avalve casing through a coupling/uncoupling mechanism which permits touncouple the valve guide member from the valve casing whenevernecessary. However, if the valve assembly unit is dislodged from thevalve casing while the endoscope is in use, aspirated body fluids orother unsanitary fluids will spill out from the valve casing. Therefore,when an endoscope is being manipulated, the valve assembly unit shouldbe securely and stably locked in the valve casing in an operativelycoupled state.

For this purpose, a coupling/uncoupling function is performed by anarcuate segmental guide groove which is provide on one of fittingportions of the valve casing and valve guide member for engagement witha locking projection on the other one of the fitting portions of thevalve casing and valve guide member, and an introductory groove which isprovided contiguously to an entrance to the guide groove forintroduction of the locking projection into the latter. A lock-infunction is performed by limiting a rotational angle of the valve guidemember relative to the valve casing to a predetermined angular rangethereby keeping the locking projection off an axially overlappingposition on the introductory groove.

In this regard, normally the guide groove and introductory groove areprovided on the inner periphery of the valve casing, while the lockingprojection is provided on the outer periphery of the valve guide member.The connector member which is connected to the valve guide isconstituted by a rigid pipe and projected radially outward from alateral side of the valve guide member of the valve assembly unit. Theconnector member can be turned about a center axis of the valve assemblyunit.

Although the connector member which is turnable about the valve assemblyunit, it does not need to be turned through 360 degrees duringmanipulation of an endoscope. From the standpoint of maneuverability ofthe endoscope, a proximal aspiration passage which is connected with theconnector member should be extended in a direction away from the body ofan operator. Therefore, in a case where the connector member is extendedto the left of a manipulating head of the endoscope, arrangements can bemade for a lock-in function in such a way as to prevent the lockingprojection from coming into alignment with the introductory groove. Theconnector member is not turned to the right of the manipulating head ofthe endoscope while manipulation of the latter, but the lockingprojection can be brought into alignment with the introductory groove toeffectuate a coupling/uncoupling function as soon as the connectormember is turned to that direction.

Various manual operating members are provided on a housing of themanipulating head, including a push button switch. Thus, a bush buttoncan be located on the housing of the manipulating head on the proximalside of the valve casing to utilize same as part of a lock-in mechanism.The push button is projected on the housing of the manipulating head tosuch a height that it comes into interference with the connector memberwhen the valve guide is turned in the valve casing in a coupled state,limiting the angular range of the turn of the valve guide member shortof a position where the locking projection is axially aligned with theintroductory groove. When the push button is depressed to permit passagethereover of the connector member, the connector member can be turnedbeyond the above-mentioned angular range to bring the locking projectioninto alignment with the introductory groove to effectuate thecoupling/uncoupling function. Thus, arrangements are made to bring thelocking projection into alignment with the introductory groove at aposition which partly coincides with a position where the connectormember is overlapped with the push button.

When a first rotation limit point for the valve assembly unit is set atone end of the arcuate guide groove where the connector member comesinto abutment against the push button, a second rotation limit point isset at the other end of the guide groove by providing a stopper wall atthe other end. Thus, the connector member is can be put in a slidingdisplacement in the guide groove in an angular range which is defined onone side of the introductory groove by the first and second rotationlimit points, effectuating the lock-in function. On the other hand, whenthe locking projection is located in an angular range on the other sideof the introductory groove, the coupling/uncoupling function iseffectuated to permit coupling and uncoupling of the valve assembly unitinto and out of the valve casing.

A stationary flange member is provided at an upper end of the valvecasing which is projected outward of the manipulating head, for abuttingengagement with a detachable flange portion on the side of the valveguide member. In order to hold the stationary and detachable flangesfast to each other, a resilient holder ring is fitted on. The holderring which is formed of a resilient material is in the form of a splitring an axial split portion to present C-shape in cross section.

A stationary flange may be formed integrally with the valve casing ifdesired. Alternatively, it can be formed by threading a nut on anexternal screw which is formed around a projected end of the valvecasing. On the other hand, a detachable flange portion can be formed onthe valve guide member contiguously to a fitting portion to put infitting engagement in the valve casing. In order to hold the stationaryand detachable flanges fast to each other, gripper portions in the formof arcuate ribs are formed at two axially spaced positions on the innerperiphery of the holder ring. Namely, the flanges are gripped betweenlower and upper gripper ribs which are spaced apart by a distancecorresponding to a sum of thicknesses of the two flanges.

The lower gripper portions are formed at the lower end of the holderring and provided with a tapered guide surface which is graduallydiverged toward the lower end of the holder ring. Under the guidance ofthe tapered guide surface, the valve assembly unit having the holderring fitted thereon can be smoothly fitted in and coupled with the valvecasing. The resilient holder ring, which is split in C-shape, can holdthe two flanges securely and stably in a gripped state, effectivelycontributing to the performance of the lock-in function mentioned above.Preferably, expander tabs are provided on the outer periphery of theholder ring in the vicinity of the split portion to facilitate itsdetachment from the valve guide member in performing thecoupling/uncoupling function.

In case the connector member is connected to a connection port at alateral side of the valve guide member as mentioned above, it ispreferred to provide flanges on the valve guide member on the upper andlower sides of the connection port of the connector member. In thisinstance, the flange on the lower side serves as the detachable flangeportion, while the flange on the upper side serves as a trigger mountportion. In addition to the above mentioned upper and lower gripperportions, preferably a third gripper portions is provided on the innerperiphery of the holder ring, the third gripper portion being broughtinto engagement with the upper flange to hold the valve guide member ina more stabilized state prior to bringing the holder ring into abutmentagainst the valve casing.

The above and other objects, features and advantages of the presentinvention will become apparent from the following particular descriptionof preferred embodiments shown in the accompanying drawings. Needless tosay, the invention is not limited to particular forms exemplified in thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective outer view of a manipulating head of anendoscope in a first embodiment of the invention;

FIG. 2 is a schematic front view of the manipulating head in FIG. 1;

FIG. 3 is a schematic view showing layout of endoscopic aspirationpassages;

FIG. 4 is a schematic sectional view of an endoscopic aspiration deviceaccording to the invention;

FIG. 5 is an exploded perspective view of the aspiration device of FIG.4;

FIG. 6 is a cross section of the aspiration device, taken on line A-A ofFIG. 4;

FIG. 7 is a schematic illustration explanatory of another example of alock-in mechanism for preventing dislodgement of a valve assembly unitfrom a valve casing;

FIG. 8 is a schematic illustration explanatory of functions of thelock-in mechanism shown in FIG. 7;

FIG. 9 is a schematic sectional view showing another example of thelock-in mechanism;

FIG. 10 is a schematic sectional view of an endoscopic aspiration devicein a second embodiment of the invention;

FIG. 11 is an exploded perspective view of the aspiration device in FIG.10;

FIG. 12 is a schematic plan view of a holder ring;

FIG. 13 is a schematic sectional view showing the holder ring which isfitted on a valve assembly unit in FIG. 10, which is disengaged andseparated from a valve casing; and

FIG. 14 is a schematic perspective view of an endoscope having theaspiration device fitted on its manipulating head.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereafter, with reference to the accompanying drawings, the invention isdescribed more particularly by way of its preferred embodiments. In theaccompanying drawings, shown in FIGS. 1 through 9 is a first embodiment,and shown in FIGS. 10 through 14 is a second embodiment of the presentinvention.

FIGS. 1 and 2 show a manipulating head of an endoscope to which thepresent invention is applicable, while FIG. 3 schematically shows alayout of endoscopic aspiration passages. In these figures, indicated at1 is an endoscope proper, which is composed of a manipulating head 2 andan elongated insertion rod or insertion rod member 3. A universalconnection cable 4 is led out from the manipulating head 2. A toolintroduction channel 5 is provided internally of the insertion rod 3 asfar as an exit opening which is opened at the fore distal end of theinsertion rod for introduction of a surgical or bioptic tool into a bodycavity. The proximal end of the tool introduction channel 5 is opened toa tool entrance way 6 on a housing of the manipulating head 2. Normally,the tool entrance way 6 is closed by a plug member 7.

The above-mentioned tool introduction channel 5 is also used as anaspiration passage and branched off an aspiration passage 11 at ajunction point internally of the manipulating head 2. On the other hand,the aspiration passage 11 is connected to an aspiration device 10including an aspiration valve and a valve operating means. Connected tothe aspiration device 10 is a fore end of a flexible proximal aspirationpassage, i.e., a proximal aspiration passage 12 on the side of a suctionsource (not shown). The aspiration device 10 controls connections of theproximal aspiration passage 12, bringing the proximal aspiration passage12 into communication with either the atmosphere or the aspirationpassage 11 as it is manipulated by a finger of an operator's hand whichgrips the manipulating head 2.

Shown in FIG. 4 are more details in construction of the aspirationdevice 10. As seen in that figure, a valve casing 14 of the aspirationdevice 10 is fixedly fitted in a housing 13 of the manipulating head 2of the endoscope. An aspiration passage 11 is connected to a lowerbottom end of the valve casing 14 (in the following description, adirection inward of the housing 13 of the manipulating head 2 isdescribed as a downward direction and a direction outward of the housing13 is described as an upward direction for the convenience ofexplanation). The valve casing 14 is provided with a constricted wallportion of a reduced diameter on and around its inner periphery,providing a sliding surface 14 a over a predetermined length in theaxial direction. By a valve member which will be described hereinlater,the valve casing 14 is divided into a first chamber 15 and a secondchamber 16 on the lower and upper sides of the sliding surface 14 a ofthe constricted wall portion, respectively.

Fitted in the valve casing 14 is a valve assembly unit 17 which iscomposed of a valve guide member 18 and a valve member 19. The valveguide member 18 is fitted in the second chamber 16 of the valve casing14, and a seal member 20 is interposed between the valve guide member 18and the valve casing 14. The valve member 19 is fitted in the valveguide member 18 and slidable linearly in the axial direction under theguidance of inner peripheral surfaces of the valve guide member 18. Arigid connector pipe 21 is fitted into the valve guide member 18 from alateral direction at an upper position of the latter, and a proximalaspiration passage 12 from a suction source is detachably connected toan outer end of the connector pipe 21. That is to say, the connectorpipe 21 is located on one lateral side of the valve guide member 18substantially at right angles relative to the longitudinal axis of thelatter, permitting to connect the proximal aspiration passage 12 on theside of the suction source from a lateral direction of the manipulatinghead 2 of the endoscope.

The valve member 19 which is fitted in the valve guide member 18 iscomposed of a body shaft 19 a which is extended in the axial directionof the valve guide member 18 and provided with a resilient valve portion22 at its lower end in sliding engagement with the sliding surface 14 aon the part of the valve casing 14. The body shaft 19 a is arranged tohave a predetermined axial length, and an annular passage 24 is formedbetween outer peripheral surface of the body shaft 19 a and innerperipheral surface of the valve guide member 18 in communication withthe connector pipe 21. An intercommunicating passage 23 which isprovided on the body shaft 19 a of the valve member 19 is constantlyheld in communication with the annular passage 24.

Provided at an upper or outer end of the body shaft 19 a is a dome-liketrigger member 25 which is formed of a resilient material and providedwith an opening 26 in a girder wall portion in communication with theatmosphere. As the aspiration trigger member 25 is pressed in or outwith a finger, the valve portion 22 is slid along the sliding surface 14a of the valve casing 14 to bring the first and second chambers 15 and16 into or out of communication with each other, while covering oruncovering the opening 26 to turn on and off the aspiration device 10.By way of the aspiration trigger member 25, the valve guide member 18and valve member 19 are connected with each other.

Normally, the aspiration device 10 is retained in an off-position shownin FIG. 4. In this position, communication between the first and secondchambers 15 and 16 is blocked by the valve portion 22 of the valvemember 19, and the connector pipe 21 is communicated with the atmospherethrough the annular passage 24 and the opening 26 in the aspirationtrigger member 25. Thus, no suction force is applied to the aspirationpassage 11. As the aspiration trigger member 25 is pushed inward fromthe off-position, the communication with the opening 26 is blocked andthe valve portion 22 is moved downward to bring the first and secondchambers 15 and 16 into communication with each other. As a consequence,the connector pipe 21 which is connected to the proximal aspirationpassage 12 on the side of the suction source is brought intocommunication with the aspiration passage 11 via the annular passage 24,intercommunicating passage 23 and the first and second chambers 15 and16 to apply the suction force in the proximal aspiration passage 12 onthe side of the suction source to the aspiration passage 11 to aspiratebody fluids through an aspiration port at the fore distal end of thetool introduction channel 4 on the insertion rod member 3.

The endoscope 1 is used repeatedly and therefore needs to be washedafter each use. Particularly, aspiration passages which are unavoidablysubjected to contamination with body fluids or the like need to bewashed completely and entirely. For this purpose, the valve assemblyunit 17 is extractable from the valve casing 14, permitting to washaspiration passages including the aspiration passage 11 and interiors ofthe valve casing 13 completely in a facilitated manner. On the otherhand, the extracted valve assembly unit 17 may be reused after washing,but preferably it is discarded after a single use.

For manipulation of the endoscope 1, an operator grips the manipulatinghead 2 in his or her hand. The proximal aspiration passage 12 which isconnected to the valve guide 18 of the valve assembly unit 17 by way ofthe connector pipe 21 may obstruct the manipulation of the endoscope 1and therefore should preferably be put out of the way of endoscopemanipulation. For this purpose, the valve assembly unit 17 is arrangedto be able to turn about its longitudinal axis relative to the valvecasing 14. Further, the connector pipe 21 can be easily turned into adifferent angular position around the aspiration device 10 by pushingsame toward a desired angular position, followed by the flexible tube ofthe proximal aspiration passage 12 which is connected to the connectorpipe 21. A seal member 20 is interposed between the valve guide member17 and the valve casing 14, so that a turning force on the connectorpipe 21 is met by a certain degree of resistance, which in turncontributes to retain the connector pipe 21 and the proximal aspirationpassage 12 stably in a desired angular position.

The valve assembly unit 17 is coupled with the valve casing 14 through acoupling mechanism as described below with reference to FIGS. 4, 5 and6.

An annular guide groove 30 is formed around the inner periphery of thevalve casing 14. On the other hand, a segmental locking projection 31 isformed around a girder of the valve guide member 18 and engaged with theguide groove 30 on the part of the valve casing 14 to preventspontaneous dislodgement of the valve guide member 18 from the valvecasing 14. This segmental locking projection 31 is slightly smaller thanthe guide groove 30 in thickness or width, and radially projected fromthe girder of the valve guide member 18 to a height which substantiallycorresponds to the depth of the guide groove 30. An introductory groove32 of the same width and depth as the guide groove 30 is formed aroundthe inner periphery of the valve casing 14 in contiguously overlappingrelation with an entrance to the guide groove 30. This introductorygroove 32 is opened to the upper end of the valve casing 14 at its outerside and communicated with an entrance portion of the guide groove 30 atthe other or inner side.

At the time of assembling the valve guide member 18 into the valvecasing 14 by fitting engagement with the latter, the segmental lockingprojection 31 on the valve guide member 18 is put into the guide groove30 of the valve casing 14 by way of the open side of the introductorygroove 32. Then, the valve guide member 18 is turned in the guide groove30 until the segmental locking projection 31 is shifted to a radialposition where it is locked in the guide groove 30 in the axialdirection. At this time, as the segmental locking projection 31 is slidalong the guide groove 30, the valve assembly unit 17 as a whole isturned relative to the valve casing 14 about the longitudinal axis ofthe latter. Thus, as long as the segmental locking projection 31 is inan axially locked position within the guide groove 30, the valveassembly unit 17 is securely retained in the valve casing 14 in such away as to preclude possibilities of its dislodgement from the valvecasing 14. Thus, the valve assembly unit 17 is detachably assembled withthe valve casing 14 by a coupling/uncoupling function which is performedjointly by the guide groove 30, introductory groove 32 and segmentallocking projection 31.

As the valve guide member 18 of the valve assembly unit 17 is turnedwithin the valve casing 14, the valve assembly unit 17 can be dislodgedfrom the valve casing 14 if the locking projection 31 is shifted to anaxially aligned position relative to the introductory groove 32 on theside of the valve casing 14. During or immediately after an aspiratingoperation, for example, the entire paths of aspiration from theaspiration passage 11 to the proximal aspiration passage 12 on the sideof a suction source are filled with body fluids or other aspiratedinternal filth, so that the aspirated body fluids can spill out throughan opening of the valve casing 14 should the valve assembly unit 17 comeoff the valve casing 14. In order to prevent this, the turning angle ofthe valve assembly unit 17 is limited to a predetermined angular rangeduring an aspirating operation by means of a rotation limitingmechanism, thereby preventing the segmental locking projection 31 frombeing turned as far as the position of the introductory groove 32.

As shown in FIG. 2, a universal connection cable 4 is led out from themanipulating head 2 of the endoscope. More particularly, compared withthe insertion rod 2 which is extended out on the front side of themanipulating head 2, the universal connection cable 4 is led out from aleft side of the housing 13 of the manipulating head 2. This is becausenormally the manipulating head 2 is gripped in a left hand of anoperator who takes a position on the right side of the manipulating head2. Therefore, the proximal aspiration passage 12 on the side of asuction source is necessarily extended leftward of the housing 13, thatis, in a direction away from the body of an operator. If located on theright side, the proximal aspiration passage 12 will obstruct themanipulation of the endoscope to a considerable degree. Therefore,unless there is an exceptional reason, the connector pipe 21 is notlocated on the right side of the manipulating head 2.

Thus, the introductory groove 32 is formed on the inner periphery of thevalve casing 14 in a position at the left side of the housing 13 of themanipulating head 2. Further, the segmental locking projection 31 on theside of valve guide member 18 is formed at a position virtually on theopposite side away from the side where the connector pipe 21 is extendedout from the valve guide member 18. Accordingly, when coupling the valveassembly unit 17 with the valve casing 14, the proximal aspirationpassage 12 is extended in a direction rightward of the manipulating head2, namely, in an opposite direction relative to the universal connectioncable 4. In this state, somehow an operator can manage to grip andmanipulate the endoscope 1 but it is very likely that manipulation ofthe endoscope 1 is hindered by the connector pipe 21 and proximalaspiration passage 12 which present themselves as obstacles in the wayof manipulation.

Therefore, when manipulating the endoscope 1, the valve assembly unit 17is always turned to the left side to take a position leftward of themanipulating head 2, keeping the proximal aspiration passage 12 in thatposition in the course of manipulation of the endoscope 1, adjusting itsangular position if necessary. Thus, while the endoscope 1 is beingmanipulated, there is no possibility of the locking projection 31 beingturned as far as the position of the introductory groove 32, that is tosay, the valve assembly unit 17 is securely locked in position in thevalve casing 14 by a lock-in function performed by the lockingprojection 31 itself.

However, the above-mentioned lock-in function is effectual as long asthe manipulating head 2 is gripped in an operator's hand. The limitationof rotational movement of the valve assembly unit 17 by the lock-infunction becomes ineffectual when the endoscope 1 is put apart from anoperator's body, for example, when put on a desk or when handed over toan assistant operator.

A number of manual operating members to be manipulated by an operatorare provided on the manipulating head 2 of the endoscope 1. For example,as shown in FIG. 2, a nose angle control member 8 is provided on themanipulating head 2 for controlling an angle of an articular anglingsection in a fore end portion of the insertion rod member 3, in thefashion of remote control. Further, usually a push button switch 33 isprovided on the manipulating head 1 to capture picture images of anintracavitary site under observation. This push button switch 33 ispushed by a finger of an operator's hand which grips the manipulatinghead 2. If desired, the push button switch 33 can be utilized to performthe lock-in function for the valve assembly unit 17.

For example, arrangements are made such that the connector pipe 21 comesto an overlapping position on the push button switch 33 when it isturned toward the proximal end as shown in FIG. 7. Further, as shown inFIG. 8, the push button switch 33 is projected on the housing 13 to aninterfering height relative to the connector pipe 21. When depressed,the push button switch 33 is pushed down to a low position indicated byimaginary line in FIG. 8, permitting the connector pipe 21 to passthereover.

With the arrangements as described above, when the locking projection 31on the valve guide member 18 is located in an axially aligned positionrelative to the introductory groove 32 on the side of the valve casing31 for the purpose of fitting the valve assembly unit 17 into the valvecasing 14, at least part of the connector pipe 21 which is extended outfrom the valve guide member 18 is located in a position over the pushbutton switch 33 on the casing 13. Namely, the introductory groove 32 ofthe valve casing 14 is provided in a position forward of the push buttonswitch 33, while the locking projection 31 is located in a positionunder the connector pipe 21.

In this state, unless the push button switch 33 is depressed, the valveassembly unit 17 cannot be turned to a position where the lockingprojection 31 is axially aligned with the introductory groove 32. Thatis to say, there is no possibility of dislodgement of the valve assemblyunit 17 from the valve casing 14 when the endoscope is being manipulatedin an ordinary fashion or when the endoscope is not being manipulated.The valve assembly unit 17 can be extracted from the valve casing 14 bydepressing the push button switch 33 and turning the valve guide member18 to bring the connector pipe 21 to a position on the depressed pushbutton switch 33.

As described above, since an operator normally stands on the right sideof the manipulating head 2, the operator will not feel inconvenience aslong as the connector pipe 21 and the ensuing proximal aspirationpassage 12 on the side of a suction source are located on the left sideof the housing 13 of the manipulating head 2 because there will arise nonecessity for turning them around to the right side of the housing 13during manipulation of the endoscope. Accordingly, turn angles of theconnector pipe 21 can be limited to the range of angle theta in FIG. 9.In this case, the position of the push button switch 33 is set at afirst limit point P. Further, as shown in FIG. 9, an arcuate guidegroove 40 is extended in a direction away from the first limit point Pas far as a stopper wall 41. Thus, the locking projection 31 can beturned as far as the stopper wall 41 which is provided at the other endof the guide groove 40 to function as a second limit point Q.

Consequently, the valve guide member 17 is turnable only in a limitedrange, i.e., in the range between the first and second limit points Pand Q on the left side of the manipulating head 2, namely, in the rangeof angle theta in FIG. 9. In this case, as indicated by imaginary linein FIG. 9, the introductory groove 32, serving to introduce the lockingprojection 31 of the valve guide member 17 into the guide groove 40, canbe located at an arbitrary position in an angular range on the rightside of the housing 13 between the first and second limit points P andQ, while the locking projection 31 is located in an angular range on theleft side. By turning the locking projection 31 until it reaches anaxially aligning position with the introductory groove 32, riding overthe push button switch 33, the valve assembly unit 17 can be extractedfrom the valve casing 14.

Now, turning to FIGS. 10 through 14, there is shown a second embodimentof the invention. In this embodiment, a valve casing and a valveassembly unit are disconnectibly coupled with each other through acoupling mechanism with locking and unlocking functions.

As shown in FIGS. 10 and 11, a valve casing 100 which is provided on amanipulating head 2 of an endoscope 1 is tapped with an external screw100 a on its outer peripheral surface, and an anchor nut 101 is threadedon the external screw 100 a in such a way as to grip a housing 13 of themanipulating head 2 between the anchor nut 101 and a stopper flange 100b which is provided on the side of the valve casing 100. Threaded on theupper end of the valve casing 100 is a stationary flange member 102,which is formed with an upper large diameter portion 102 a and a lowersmaller diameter portion 102 b on its outer peripheral side. The largeand small diameter portions 102 a and 102 b are intervened by atransitory stepped wall surface 102 c which is disposed perpendicularlyto the center axis of the valve casing 100.

Substantially in the same way as in the foregoing first embodiment, avalve assembly unit 103 is composed of a valve guide member 104 and avalve member 105. The valve guide member 104 is formed with a detachableflange portion 206. At a predetermined distance from the detachableflange portion 106, a rim fitting portion 107 is provided on an upperportion of the valve guide member 104 to receive a rim portion at thelower end of a skirt portion of a dome-like aspiration trigger member25. A connector pipe 108 is connected to a reduced diameter portion ofthe valve guide member 104 between the detachable flange portion 106 andthe rim fitting portion 107.

The valve assembly unit 103 is coupled with the valve casing 100 byinserting a lower portion of the valve guide member 104 into the valvecasing 100. A seal member 109 is interposed between the inserted lowerportion of the valve guide member 104 and the valve casing 100. Oninsertion, the valve guide member 104 is pushed in until the detachableflange portion 106 comes into abutting engagement with the stationaryflange member 102 on the side of the valve casing 100.

The valve assembly unit 103 is axially fixed to the valve casing 100,with the detachable flange portion 106 in abutting engagement with thestationary flange member 102. In this instance, a holder ring 110 isadopted for this purpose. The holder ring 110 is formed of a resilientmaterial like metal or rubber, substantially in the shape of a roundtube having a split portion 110 a at one radial angular position topresent a C-shape in cross section. In the proximity of the splitportion 110 a, the holder ring 110 is provided with expander tabs 111which are prominently projected in a radially outward direction on theopposite sides of the split portion 110 a. By spreading apart theexpander tabs 111, the split portion 110 a is widened through resilientdeformation. Thus, the holder ring 110 returns to its original shapeupon removing an external spreading force.

As clear from FIG. 12, at diametrically opposite positions on the innerperiphery of the holder ring 110, three sets of gripper ribs 112, 113and 114 are projected in radially inward directions. Lowermost gripperribs 112 are adapted to be brought into abutting engagement with thelower surface of the stationary flange member 102, while theintermediate gripper ribs 113 are adapted to be brought into abuttingengagement with the top surface of the detachably flange portion 106 ofthe valve guide member 104. The uppermost gripper ribs 114 are adaptedto be brought into abutting engagement with the valve manipulator mountportion 107 of the valve guide member 104. Thus, when the valve assemblyunit 103 is assembled into the valve casing 100, the stationary flangemember 102 and the detachable flange portion 106 are gripped fast toeach other between the lower gripper ribs 112 and the intermediategripper ribs 113.

As mentioned above, the uppermost gripper ribs 114 are adapted to bebrought into abutting engagement with the lower surface of themanipulator mount portion 107. As shown in FIG. 13, by the intermediateand uppermost gripper ribs 113 and 114, the holder ring 110 is fixedlyretained on the valve assembly unit 103 even when the latter isseparated from the valve casing 100. Therefore, the valve assembly unit103, having the holder ring 110 fitted thereon beforehand, can be easilycoupled with the valve casing 100 simply by pushing same into the valvecasing 100 from above. In order to ensure smooth coupling of the valveassembly unit 103 with the valve casing 100, the lowermost gripper ribs112 are each provided with a tapered surface 112 a at a lower end, whichis inclined radially outward in the downward direction. Thus, under theguidance of the inclined surfaces 112 a, the lowermost gripper ribs 112are urged to ride over the stationary flange member 102 and fit inposition by a snap action.

Further, the holder ring 110 is provided with a notch 115 to a halfwaypoint from its upper end to avoid interference with the connector pipe109 which is extended radially outward from the valve guide member 104.

By adoption of the construction as described above, the valve assemblyunit 104 can be assembled with the valve casing 100 by means of theholder ring 110 as shown in FIG. 14. In this state, the stationaryflange member 102 which is provided integrally on the side of the valvecasing 100 is securely gripped between the lowermost and intermediategripper ribs 112 and 113 of the holder ring 110 together with thedetachable flange portion 106 on the side of the valve guide member 104of the valve assembly unit 104. Thus, there is no possibility of thevalve assembly unit 103 getting detached from the valve casing 100during manipulation of the endoscope 1.

Further, at the time of disconnecting the valve assembly unit 104including the proximal aspiration passage 12 from the valve casing 100after use for washing purposes, for example, the holder ring 110 can bedetached from the valve assembly unit 104 by pushing the expander tabs111 away from each other to spread the split portion 110 a wider. Thus,in this manner the valve assembly unit 104 is easily separable from thevalve casing 100.

As described above, by spreading the split portion 110 a in the holderring 110, the valve assembly unit 104 can be separated from the valvecasing 100. In this regard, the width of the split portion 110 a must besmaller than 180 degrees, but it is possible to employ a relativelynarrow split portion 110 a form the standpoint of enhancing thestability in assembled state or to employ a relative relatively widesplit portion 110 a from the standpoint of facilitating its attachmentand detachment.

What is claimed:
 1. An endoscopic aspiration device for use on amanipulating head of an endoscope, to which a proximal end of anelongated insertion rod member is connected, said endoscopic aspirationdevice comprising a valve casing provided on said manipulating head incommunication with an aspiration passage leading to a fore distal end ofsaid insertion rod member, and a valve assembly unit composed of anassembly of a valve member and a valve guide member having a connectormember extended out for connection to a proximal aspiration passage onthe side of a suction source, said valve member being put in a slidingdisplacement along said valve guide member to bring said aspirationpassage into and out of communication with said proximal aspirationpassage, characterized in that said endoscopic aspiration devicecomprises: a coupling mechanism provided between said valve casing andsaid valve guide member of said valve assembly unit and adapted tocouple said valve guide member with said valve casing in such a way asto permit said valve assembly unit to make turns about a center axis ofsaid valve casing on said manipulating head; said coupling mechanismincluding a coupling/uncoupling mechanism with a function of bringingsaid valve guide member of said valve assembly unit into and out offitting engagement with said valve casing, and a lock-in mechanism witha function of retaining said valve guide member in a coupled statewithin the valve casing, preventing spontaneous dislodgement of saidvalve assembly unit from said valve casing in said turns of said valveassembly unit; and wherein said coupling/uncoupling mechanism is aholder ring formed of a resilient material and the lock-in mechanismincludes a first and second sets of gripper portions adapted to securelygrip therebetween a stationary flange member at a projected of saidvalve casing from upper and lower sides, together with a detachableflange portion formed on the side of said valve guide member of saidvalve assembly unit for abutting engagement with said stationary flangemember, said holder ring being formed in C-shape in cross section andprovided with an expandable split portion.
 2. An endoscopic aspirationdevice as set forth in claim 1, wherein said valve casing is providedwith an external screw on an outer peripheral surface thereof forthreaded engagement with said stationary flange in the form of a nut,said valve guide member is formed with a fitting portion contiguously tosaid detachable flange portion, for fitting engagement in said valvecasing.
 3. An endoscopic aspiration device as set forth in claim 1,wherein said holder ring is provided with said gripper portions at aplural number of radially and axially spaced positions on the innerperiphery thereof, including lowermost and intermediate gripper portionsbeing axially spaced from each other by a distance corresponding to asum of thicknesses of said stationary flange member and said detachableflange portion.
 4. An endoscopic aspiration device as set forth in claim3, wherein said lowermost gripper portion is formed at a lower end ofsaid holder ring and provided with a tapered surface on an innerperipheral side, said tapered surface being diverged radially outward ina downward direction.
 5. An endoscopic aspiration device as set forth inclaim 1, wherein said holder ring is provided with expander tabsprominently projected in a radially outward direction in the vicinityand on the opposite sides of said split portion.
 6. An endoscopicaspiration device as set forth in claim 1, wherein said connector memberis connected to a lateral side of said valve guide member between saiddetachable flange portion and a trigger mount flange formed at a spacedposition on the upper side of said detachable flange, and said holderring is provided with a third set of gripper portions in addition tosaid first and second sets of gripper portions, for abutting engagementwith a lower side of said valve trigger mount flange.